The Multifactorial Study On Circadian Rhythm Of Pulp Sensibility In Aged People

This research studied the chronobiology characteristic of pulp sensibility systematically. We found the circadian rhythm of pulp Sensibility, and discussed the influence of age, sex, tooth type, and chronic systemic diseases on the rhythm variations of pulp sensibility. This study may serve to enrich the theory of pulp-chronobiology, and guide the diagnosis and treatment of dental diseases to the aged.In this study, the first lower molar of every healthy volunteer was inspected its pulp sensitivity threshold. Each inspection was implemented every 4 hours, from 8:00 in the first morning to 8:00 in the next morning, totally 7 times during 24 hours. Then all the pulp sensibility threshold values of each volunteer were analyzed by Halberg methods for cosinor-rhythmometry. Following the same method, we compared the chronobiology characteristic of pulp sensibility, between the young, middle-aged and aged group, still between different sex groups, and different tooth groups. We also explored the circadian rhythm of pulp sensibility in aged diabetic patients, hypertensive patients. The results were described as follows:1. The pulp sensibility threshold value of human changed rhythmically in 24 hours, fitting well to a cosine curve. The acrophase and bathyphase appeared at 0:00 and 12:00 separately, namely, pulp feeling is bluntest at 0:00, and most sensitive at 12:00.2. The circadian rhythm of pulp sensibility changed according to age. The trend and time-axis locations of the rhythm curve were similar between each age group. However, the pulp threshold value was lower in aged people than the young, and the lowest in middle-aged people. Besides, the extent of rhythm fluctuation was the least in middle-aged people. It seemed that, the circadian rhythm of pulp sensibility tended to be tempered in middle age.3. The pulp sensibility circadian rhythm was found in both aged males and females. The trend and time-axis locations of the rhythm curve were similar between the two sexes. The pulp sensory threshold was a little higher in females than in males, but was not significant statistically.4. The pulp sensibility circadian rhythm was found in both the incisors and molars of aged people. The trend and time-axis locations of the rhythm curve were similar between incisors and molars, However, the pulp threshold value was higher in molars than incisors, and the amplitude fluctuation of the rhythm was greater in molars than incisors.5. The pulp sensibility threshold value of diabetic aged people changed rhythmically in 24 hours, fitting well to a cosine curve. The acrophase and bathyphase appear at 4:00 and 16:00 separately, which moved 4 hours rightward on the time-axis compared with the healthy aged people. There was no difference in the circadian rhythm between two sexes.6. The pulp sensibility threshold value of hypertensive aged people changed rhythmically in 24 hours, fitting well to a cosine curve. The acrophase and bathyphase appear at 4:00 and 16:00 separately, which moved 4 hours rightward on the time-axis compared with the healthy aged people. However, only the male group presented this temporal pattern. The female group had almost the same temporal rhythm with the healthy.Based on the findings of this study, it was concluded that the pulp sensibility of human altered according to circadian rhythm, fitting to a cosine curve. The acrophase and bathyphase appear at 0:00 and 12:00 separately. There was no difference in the circadian rhythm between aged males and females. The pulp threshold value and the amplitude fluctuation of the rhythm were greater in molars than incisors. Diabetes, hypertension may lead to a movement of pulp sensibility circadian rhythm on the time-axis, but not for hypertensive females.